Preparation of alkyl aryl sulfonates of reduced viscosity



United States Patent PREPARATION OF ALKYL ARYL SULFONATES OF REDUCED VISCOSITY No Drawing. Application June 24, 1950, Serial No. 170,255

2 Claims. (Cl. 252-161) This invention relates to new and useful hydrocarbon compositions suitable for conversion to magnesium alkyl benzene sulfonate detergents and, in particular, it relates to improved alkyl benzene hydrocarbon mixtures suitable for the production of improved low viscosity slurries of such detergents.

Magnesium alkyl benzene sulfonate detergents represent an important group in the class of alkyl aryl sulfonate detergents. They are prepared by condensing (alkylating) benzene with an olefin, an olefin polymer, or an alkyl halide to form mixtures of long-chain monoalkyl benzene hydrocarbons containing from to 18 carbon atoms in the alkyl chain, sulfonating the mixture, and neutralizing the resulting alkyl benzene sulfonic acids with a slurry of an alkaline magnesium compound to obtain a final aqueous slurry of magnesium monoalkyl benzene 'sulfonates suitable for eventual processing to produce a solid, particle-form detergent material.

However, heretofore, it has been considered an impossibility to prepare such aqueous slurries having a solid content of magnesium alkyl benzene sulfonate detergent in excess of 40% by weight, without encountering serious difliculties in handling the slurries, owing to the high viscosity which interferes with pumping and flow of these materials through the lines of the processing plant. Magnesium alkyl benzene sulfonate detergent slurries having a solid content in excess of are so viscous that they cannot be handled through the lines in the plant with the aid of conventional pumping machinery. Dilution with water to a consistency suitable for unimpeded transfer through the lines by conventional pumping equipment is uneconomical; furthermore, when the slurry is thus greatly diluted with water, the product resulting upon reduction of the slurry to the solid form, e. g., to beads by spray-drying, is less satisfactory. The beads are friable and possess a low tensile strength,.which fact contributes to the formation of fines and irritating dust. Moreover, a higher consumption of fuel and energy is necessary to effect evaporation of the water of dilution from the magnesium alkyl benzene sulfonate slurry. When the diluted slurries are shipped to a processing plant by tank car, the freight charges are substantially increased by the presence of an excess of water. I have now found that the addition of a minor amount of a low molecular weight mononuclear aromatic hydrocarbon boiling in the range from about 179 F. to about 400 F. to the long-chain monoalkyl benzene prior to sulfonation secures remarkably reduced viscosities in magnesium monoalkyl benzene sulfonate detergent slurries upon eventual sulfonation of the monoalkyl benzene base-stock so diluted, and subsequent neutralization of the sulfonated product mixture with an alkaline magnesium compound.

The viscosity of detergent slurries derived from monoalkyl benzene containing the low molecular weight aromatic hydrocarbon in accordance with my invention is usually equal to less than 100 poises at 135 F. (Brookfield' viscometer at 10 R. P. M.) as compared with the viscosities in excess of 1000 poises at 135 F. observed for the detergent slurries derived from the same monoalkyl benzene containing no added low molecular weight aromatic hydrocarbon. The slurries produced from monoalkyl benzene containing a" minor amount of such a low molecular weight mononuclear aromatic hydrocarbon additive can be handled through conventional pumping equipment and pipe-lines without difliculty, although these slurries contain 40, 50 and even as much as 55 percent by weight of solids.

The mixture containing the added low molecular weight mononuclear aromatic hydrocarbon can be sulfonated by any conventional method, e. g., with the aid of sulfuric acid, oleum, or S03, and the sulfonation product is then neutralized with a slurry of a magnesium alkaline compound, e. g., magnesium oxide andfmagnesium hydroxide. After sulfonation with sulfuric acid, preferably fuming acid, or with sulfur trioxide, the sulfonation reaction mixture is settled to permit separation and withdrawal of the excess of sulfuric acid. In most cases, upon settling and removal of excess sulfuric acid, the sulfonation product will contain from to sulfonic acid and this concentrated sulfonic acid is reacted with the magnesium alkaline compound. The final neutralized pumpable slurry of magnesium sulfonate detergent which may contain a minor amount of magnesium sulfate formed by neutralization of residual sulfuric acid may then be pumped through connecting lines to an appropriate treating unit where it will be reduced to-the particulate solid form, e. g., by spray-drying. When magnesium carbonate is the neutralizing agent for the sulfonation reaction product, the conditions of neutralization will be modified in accordance with the conventional practices of those skilled in the art.

The low molecular weight mononuclear aromatic hydrocarbon to be added to the base stock of monoalkyl benzene is selected from the group of low molecular weight mononuclear aromatic hydrocarbons boiling in the range from about 179 F. to about 400 F. These mononuclear aromatic hydrocarbons comprise benzene and the various readily sulfonatable monoalkyl and dialkyl substituted benzenes containing an aggregate of not more than 5 alkylcarbon atoms. The term alkyl carbon atoms as employed in this specification hereinafter shall mean carbon atoms present in the alkyl chain or chains of an alkyl aromatic hydrocarbon having one or more alkyl side chains. The mononuclear, monoalkyl and dialkyl hydrocarbons contemplated as operative additives to long-chain monoalkyl benzene base-stock for the eventual preparation of alkyl benzene sulfonate detergents include toluene; xylenes; ethyl benzene; diethyl benzenes; ethyl methyl benzenes; cumene; ethyl propyl benzenes; methyl butyl benzenes; butyl benzenes; propyl benzenes; and the like, as well as mixtures of such monoalkyl and dialkyl benzenes containing an aggregate of not more than 5 alkyl carbon atoms per molecule. For instance, mixtures of xylenes produced in the hydroforming treatment of petroleum fractions may be successfully used.

Ordinarily these low-boiling, low-molecular weight aromatic hydrocarbons are added in amounts ranging from about 0.5 to about 5.0% byweight of the base-stock, although higher amounts will also be operative. In some cases, somewhat lower amounts of the diluent will be effective; thus, an addition of as little as 0.3% by weight of a xylene is found to be sufilcient to secure the desired reduction in viscosity. For practical. purposes, however, the preferred range of low-boiling alkyl'aromatic hydrocarbon additions to the base-stock lies between about 1.0 and about 3.0% by weight.

All of these low molecular weight mononuclear aromatic hydrocarbons, when added in minor amounts as specified hereinbefore to the base-'stockof CiotoCia monoalkyl benzenes, undergo the same reactions of sulfonation and neutralization as the base-stock containing them and are finally converted to the corresponding maamsiumx l a bana a :s n c d a, uesium mono? .and dialltylbenzene sulfonates, containing and, aggregate-of less than about 6 alkyl carbon atoms. The relative proportions of; these magnesium sulfonates inthe slurry of magnesiumgallsyl benzene sulfonate detergent .containing firo m. L0 to l -8 carbon atoms in the chain ran-geirom about 0.6 to about 6.0%. and preferably ifromabout 1.2 to about 3.5%, based on the, weight of the active magnesium alkyl benzene sulfonate detergent, in order'toinsure a pumpable viscosity equalto. 100. poisespr less at 135 F. of the detergent nts The base stocls-Efor-thepreparation of magnesium C10 Kit-G1}. alkyl henaegesulfpnate slurries of my invention mav n kcn. mcnee va s y o lk l z n hydrocarbpn zw th n l syt cha econ a nina m 10 to 18 carbon at ,s- Suitab e led y be p o y .allgylati not 'bengene-with-olefinscontaining'from 10 to The viscosity in all instances was less than about 100 poises at 135 F. (Brookfield viscometer at 10 R. P. M.).

The remarkable reduction of viscosity secured by my invention may be seen from the following Table I, in which are tabulated the results of viscosity determinations made with the aid of a Brookfield viscometer on a number of slurries having a solid content of about 5.2 to 53% magnesium alkyl benzene sul-fonate detergent derived from various base-stocks of a representative alkyl benzene having from 12 to 15 carbon atoms in the alkyl chain, to which minor amounts of a low molecular weight mononuclear aromatic hydrocarbon were added in accordance with my invention. The average extent of sulfonation was about 98%, approximately 1.52.0% of hydrocarbon oil remaining unsultonated. The table shows that the addition of such low boiling aromatic hydrocarbons in the previously mentioned preferred range from about 1.0 to about 3.0%, based on the weight of the base stock, radically reduces the viscosity of the ultimately produced. magnesium alkyl benzene sulfonatedetergent slurry.

TABLE I Effect of addition of a low molecularweight mononuclear aromatic hydrocarbon to representative C12-C'15 alkyl benzene base-stocks 0n viscosity of ultimate magnesium alkyl benzene sulfonate detergent slurries Neutralized Viscosity at and Sultanated 135F. after Percent Additive in Settling for Run Composition (Base-Stock+Additive) Weight Percent by 24 hours No. Additive Wt. Based on (Brookfleld Total Mixture viscometer of Detergent at'lO R.P.M.) and Additive in Pulses AlkylzBenzene Base-Stock A boiling from 511-575? 1, 000 Alkyl Benzene Base-Stock B boiling from 508-590FF 1, 000 AlkylBenzene Base-Stock A+Tertiary Butyl Benzene 1.0 1 23 91 0. O. 61 102 Alkyl Benzene Base-Stock A +Xylene. 1. 5 2.03 54 do 0.5 0. 68 68 Alkyl Benzene Base-Stock B+Mixture of Predominantly Xylene Hy- 3. 0. 3.73 47. 5 drpcarbons from Hydroforming Treatment of Petroleum.

Alkyl Benzene Base-Stock B+Benzene 3.0 4. 7 75:0

18, carbon atom. and preferably from 12 to 15 carbon atoms, or with olefins Produced, by. theFischer-Tropsch synthesis. Thus, stocks boiling within the range from about 475 'F. to about 650 F. and obtained by condensation of benzene with propylene polymers containing from to 1 8 carbonatoms, and preferably from 12 to carbon atoms, in .the presence of alkylation catalysts such as H2804, AlCls or. HF, may be used.

Alkyl benzenes obtained by alkylating benzene with normal butene polymers,containing from 12 to 18 carbon atoms, may also be used as base-stocks. Likewise, the so-called keryl benzenes? produced by alkylation of benzene with a chlorinated kerosene fraction and containing from 10 to 18 carbonatoms, and preferably from 12 to 15 carbon atoms, in, the alkyl chain, also represent suitable base-stocks which, upon the addition of a low molecular weight mononuclear aromatic hydrocarbon in accordance with my. invention, may be processed to produce a pumpable low. viscosity magnesium alkyl benzene sulfonate detergent slurry;

The reduction in viscosity of a magnesium alkyl benzene sulfonate detergent slurry in accordance with the inyention isparticularly pronounced when suflicient time beenallowed for the neutralized slurry to settle upon neutralization andtorelease the air enclosed in the fresh slurry; LOWrViSCQSiIY detergent slurries with densities ran-gingfrom 6,5 .to abont 8.5 pounds per gallon were obtained upon addition from about 0.5 to about 5.0% by weightof aneffectivelow molecular weight mononuclear e pmatiehy te a bqa to amqn lk nz as -s qq ltein esj em 0 mlfifl fiwnatqtiltz t the al le n- Tests were made to ascertain whether or not, the addition of a low molecular weight mononuclear aromatic hydrocarbon to the base-stock of a C10 to C13 monoalkyl benzenev would affect the performance of the ultimate magnesium alkyl benzene sulfonate detergent product. Detergency, foaming and wetting power of a representative sample of a magnesium. alkyl benzene sulfonate detergent derived from. a mixture of monoalkyl benzenes. having from 12 to 15 carbon atoms in the alkyl chain, to which xylene has been added inan amount of 1.5% by weight in accordance with the invention, were compared with detergency, foamingand wetting power of a magnesium alkyl benzene sulfonate detergent derived from an identical base-stock, but in theabsence of xylene. The basestock for this-detergent was produced by alkylating benzene with tetramers and pentarners of propylene, and the results of these tests are shown in. Table II.

The detergency values in T ablell were determined by launderometer tests- Uniformly soiled swatches. of cotton were subjected, to a series of four consecutive washings in solutions of magnesium alkyl benzene sulfonate detergent of different concentrations (0.1, 0.15, 0.2, 0.3%), the hardness of water being 300 parts per million.

The soil to be removed was uniformly applied to the cotton swatches as a paste made of oil, tallow and carbon black. The tests were efiected under conditions usually prevailing in commonlaundering processes, the procedure being standardized to give reliable results compa a le. w he a t al practice. Th e pe at r elqyedsi hese. te ts as. b u 0 De rg nry.

ratings were computed with reference to an arbitrarily chosen standard, namely, a whiteness level, or detergency, obtainable with the 0.4% concentration of a well-known household soap in hard water (300 p. p. m.), designated as the Soap Index and assumed to equal 100.

Foam heights were determined in accordance with the standard procedure of the Ross and Miles Tests, described in Oil And Soap, vol. 18, p. 99, (1944). The concentration of detergent in these foam height determinations was 0.1% with varying amounts of lard oil added to the aqueous detergent solutoin. Wetting times were determined by the Draves method (using a 3 g. hook), both in distilled water and in hard water, for two difieren-t concentrations of detergent (0.05 and 0.1%).

TABLE II Comparison of surface-active properties of magnesium sulfonate detergent slurry derived from C12 to C15 alkyl (polypropylene) benzene with and without addition of xylene Base Stock Base-Stock Coneen- Alone +15% Detergeney tration of Xylene Detergent in Percent Soap Index Soap Index Launderometer Tests: Hard i Water (300 p. p. m.), Oily Soil 2 84 0:3 I90 I91 0.1%" Concentration Foam Foam of Deter- Height Height gent+% in mm. in mm. Lard Oil 0 176 178 i it it Foa i u 40 45 10 29 30 18 21 Concen- Wetting tration of Time in Time In Detergent Seconds Seconds in Percent The test data tabulated above conclusively indicate that the detergency, foaming and wetting of the lowviscosity sulfonate detergent, produced from the base stock to which a low molecular weight mononuclear hydrocarbon has been added in accordance with my invention, are substantially equivalent to the detergency, foaming and wetting of a high-viscosity sulfonate detergent produced from the base-stock which contained no low molecular weight mononuclear aromatic hydrocarbon additive.

In conclusion, it should be understood that the aforegiven description and the experimental data are illustrative only, and that any variation or modification of my invention which conforms with the spirit and the scope thereof should be included Within the terms of the appended claims.

This application is a continuation-in-part of my application Serial No. 167,697 filed June 12, 1950, and now abandoned.

I claim:

1. A sulfonatable hydrocarbon mixture comprising polypropylene benzene having from 12 to 15 carbon atoms in the polypropylene group and about 1.5% by xylene.

2. A process for producing detergent slurries of reduced viscosity having a solids content of in excess of 40% by weight and containing a magnesium monoalkyl benzene sulfonate as the active detergent ingredient which comprises cosulfonating a mixture of polypropylene benzenes having from 12 to 15 carbon atoms in the polypropylene group and about 1.5% by weight of xylene, neutralizing the sulfonation product mixture with a slurry of an alkaline magnesium compound and recovering a pumpable slurry of the magnesium alkyl benzene sulfonates.

References Cited in the file of this patent UNITED STATES PATENTS 2,437,356 Hill Mar. 9, 1948 2,456,119 Friedman et al. Dec. 14, 1948 2,477,383 Lewis July 26, 1949 2,615,847 Thompson Oct. 28, 1952 

1. A SULFONATABLE HYDROCARBON MIXTURE COMPRISING POLYROYLENE BENZENE HAVING FROM 12 TO 1.5 CARBON ATOMS IN THE POLYPROPYLENE GROUP AND ABOUT 1.5% BY XYLENE.
 2. A PROCESS FOR PRODUCING DETERGEENT SLURRIES OF REDUCED VISCOSITY HAVING A SOLIDS CONTENT OF IN EXCESS OF 40% BY WEIGHT AND CONTAINING A MAGNESIUM MONOALKYL BENZENE SULFONATE AS THE ACTIVE DETERGENT INGREDIENT WHICH COMPRISES COSULFONATING A MIXTURE OF POLYPROPYLENE BENZENES HAVING FROM 12 TO 15 CARBON ATOMS IN THE POLYPROPYLENE GROUP AND ABOUT 1.5% BY WEIGHT OF XYLENE, NEUTRALIZING THE SULFONATION PRODUCT MIXTURE WITH SLURRY OF AN ALKALINE MAGNESIUM COMPOUND AND RECOVERING A PUMPABLE SLURRY OF THE MAGNESIUM ALKYL BENZENE SULFONATES. 